The general area of skin biology that is considered in this application is the characterization of epidermal development. In specific, this proposal focuses on identifying that molecules that control the initial steps of skin formation. The skin is a highly complex tissue that is essential to many aspects of life. However, before the skin performs its critical tasks, it must be instructed to form. The epidermis is generated from the germ layer known as the ectoderm. We recently discovered molecules that appear critical to the decision of the ectoderm to form the epidermis. These exciting findings provide an assay system, a source of tissue that contains the key regulators of skin development, as well as means to identify the key regulators by subtraction hybridization methods. With these tools, regulatory molecules that control akin development will be identified. All too frequently, the steps of skin formation are altered. These alterations of the skin occur in many settings including dermatoses, burns, aging, and with sun exposure. By identifying and characterizing the key molecules that control skin development, it may be possible to uncover novel strategies to repair the abnormal skin.